Signature of thunderstorm induced acoustic and gravity waves at low latitude Indian sector

Abstract

This study reports thunderstorm-generated acoustic and gravity waves from a tropical location using newly launched Indian navigation system NavIC for the first time. The detection of acoustic wave components in travelling ionospheric disturbance (TID) measurement is very significant. In compared to acoustic wave gravity wave signature is more ubiquitous because gravity wave propagates in thermospheric altitude by dissipative filtering process. The turbulent nature in plasma characteristics due to strong vertical drift and plasma motion in lower latitude region generate strong scintillation effect and plasma bubble. Large temperature gradient at thermospheric altitude also provides a strong attenuation effect in this region for comparatively high frequency acoustic wave. We have found the TID signatures on TEC variation for acoustic wave up to 0.4 TECU for both the days whereas gravity wave induced signatures went up to 0.8 TECU. Measurements using GPS signal validate signatures obtained from the NavIC signal. The study shows the potential of application of NavIC system for middle atmosphere as well as thermospheric study and understanding of coupling process between various atmospheric layers in tropical region which is not well known so far.